Trem2 Promotes Foamy Macrophage Lipid Uptake and Survival in Atherosclerosis
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE231659 | GEO | 2023/05/08
REPOSITORIES: GEO
Similar Datasets
Project description:Trem2 Promotes Foamy Macrophage Lipid Uptake and Survival in Atherosclerosis
| PRJNA967260 | ENA
Project description:Macrophages in atherosclerotic aorta are major population in lesion and contributes to lesion formation by becoming foam cells. To investigate in vivo transcriptome profiles of those macrophages, we extracted foamy and non-foamy macrophages from atherosclerotic aorta using lipid probe-based flow cytometry sorting. Our data indicates that intima non-foamy and foamy macrophages show different mRNA expressions. Rather than non-foamy macrophages, foamy macrophages expressed more genes related to cholesterol metabolism, oxidative phosphorylation, lysosome and so on. The non-foamy macrophages expressed more genes related to immune response (Il-1b related pathways, TNF, TLR signaling pathways) than foamy macrophages.
2018-08-30 | GSE116239 | GEO
Project description:Trem2 Agonist Reprograms Foamy Macrophages to Promote Atherosclerotic Plaque Stability
| PRJNA1078390 | ENA
Project description:Atherosclerosis-associated vascular disease is the leading cause of death worldwide. Clinical and experimental data demonstrated that circulating monocytes internalize plasma lipoproteins and become lipid-laden foamy cells in hypercholesterolemic subjects. This study was designed to identify the endocytic mechanisms responsible for foamy monocyte formation, perform functional and transcriptomic analysis of foamy and non-foamy monocytes, and characterize specific monocyte subsets in the circulation from normocholesterolemic controls and hypercholesterolemic patients. The presence of foamy monocytes was confirmed in hypercholesterolemic mice and humans via flow cytometry analysis. High resolution scanning electron microscopy (SEM) and quantification of FITC/TRITC-dextran internalization demonstrated macropinocytosis stimulation in human (THP-1) and wild type murine monocytes in vitro. Stimulation of macropinocytosis induced foamy monocyte formation in the presence of unmodified, native LDL (nLDL) and oxidized LDL (ox-LDL) in vitro. Genetic blockade of macropinocytosis (LysMCre+ Nhe1f/f) inhibited foamy monocyte formation in hypercholesterolemic mice in vivo and attenuated monocyte adhesion to atherosclerotic aortas ex vivo. qRT-PCR quantified mRNA levels of major scavenger receptors (SR) in foamy and non-foamy monocytes and identified CD36 as a major SR increasing in response to lipid loading. Deletion of CD36 (Cd36-/-) inhibited foamy monocyte formation in hypercholesterolemic mice. Mechanistic studies identified NADPH oxidase 2 (Nox2)-derived superoxide (O2⋅−) as an important downstream signaling molecule stimulating macropinocytosis in monocytes. Bulk RNA-sequencing characterized transcriptional differences between non-foamy and foamy monocytes and macrophages. Flow cytometry analysis of CD14 and CD16 expression demonstrated a significant increase in intermediate monocytes in hypercholesterolemic patients compared to normocholesterolemic controls. These results provide novel insights into the mechanisms of foamy monocyte formation and potentially identify new therapeutic targets in the treatment of atherosclerosis.
2024-12-26 | GSE278101 | GEO
Project description:To elucidate the impact of Trem2 agonist on aortic gene expression during atherosclerosis.
2024-04-18 | GSE256189 | GEO
Project description:After spinal cord injury (SCI), infiltrating macrophages undergo excessive phagocytosis of myelin and cellular debris, forming lipid-laden foamy macrophages. To understand their role in the cellular pathology of SCI, investigation of foamy macrophage phenotype in vitro revealed a unique inflammatory profile, increased reactive oxygen species (ROS) production, and mitochondrialdysfunction. Bioinformatic analysis identified PI3K as a regulator of inflammation in foamy macrophages, and pharmacological inhibition of this pathway decreased lipid content and inflammatory cytokine and ROS production in these cells. Macrophage-specific inhibition of PI3K using liposomes significantly decreased foamy macrophages at the injury site after a mid-thoracic contusive SCI in mice. RNA sequencing and in vitro analysis of foamy macrophages revealed increased autophagy after PI3K inhibition as a potential mechanism for reduced cellular lipid accumulation. Together, our data suggest that formation of pro-inflammatory foamy macrophages after SCI is due to activation of PI3K signaling that leads to decreased autophagy.
2023-12-05 | GSE237511 | GEO
Project description:Formation of foam cell macrophages (FCMs), which sequester extracellular modified lipids, is a key event in atherosclerosis. How lipid loading affects macrophage phenotype is controversial, with evidence suggesting either pro- or anti-inflammatory consequences. To investigate this further, we compared the transcriptomes of foamy and non-foamy macrophages (NFMs) that accumulate in the subcutaneous granulomas of fed-fat ApoE null mice and normal chow fed wild-type mice in vivo. Consistent with previous studies, LXR/RXR pathway genes were significantly over-represented among the genes up-regulated in foam cell macrophages. Unexpectedly, the hepatic fibrosis pathway, associated with platelet derived growth factor and transforming growth factor-? action, was also over-represented. Several collagen polypeptides and proteoglycan core proteins as well as connective tissue growth factor and fibrosis-related FOS and JUN transcription factors were up-regulated in foam cell macrophages. Increased expression of several of these genes was confirmed at the protein level in foam cell macrophages from subcutaneous granulomas and in atherosclerotic plaques. Moreover, phosphorylation and nuclear translocation of SMAD2, which is downstream of several transforming growth factor-? family members, was also detected in foam cell macrophages. We conclude that foam cell formation in vivo leads to a pro-fibrotic macrophage phenotype, which could contribute to plaque stability, especially in early lesions that have few vascular smooth muscle cells. Samples (n=4/group): Foam cell macrophages (FCM) isolated from inflammatory sponges placed in ApoE null mice fed a high-fat diet (n=4), non-foamy macrophages (NFM) isolated from inflammatory sponges placed in control mice fed a normal diet (n=4).
2015-07-23 | E-GEOD-70126 | biostudies-arrayexpress
Project description:TREM2 is a microglial-specific gene implicated in late-onset Alzheimer's Disease (AD). Recent studies have identified that Trem2-deficient mice exhibit transcriptional changes in microglial gene expression that minimize the upregulation of lipid metabolism and lysosomal genes in AD disease models. We detect similiarly attenuated expression of lipid metabolism genes in microglia isolated from brains of aged Trem2 knockout mice.
2019-12-21 | GSE134031 | GEO
Project description:Microglia are phagocytic cells that survey the brain and perform neuroprotective functions in response to tissue damage, but their activating receptors are largely unknown. Triggering receptor expressed on myeloid cells 2 (TREM2) is a microglial immunoreceptor whose loss-of-function mutations in humans cause presenile dementia, while genetic variants are associated with increased risk of neurodegenerative diseases. In myeloid cells, TREM2 has been involved in the regulation of phagocytosis, cell proliferation and inflammatory responses in vitro. However, it is unknown how TREM2 contributes to microglia function in vivo. Here, we identify a critical role for TREM2 in the activation and function of microglia during cuprizone (CPZ)-induced demyelination. TREM2-deficient (TREM2(-/-)) mice had defective clearance of myelin debris and more axonal pathology, resulting in impaired clinical performances compared to wild-type (WT) mice. TREM2(-/-) microglia proliferated less in areas of demyelination and were less activated, displaying a more resting morphology and decreased expression of the activation markers MHC II and inducible nitric oxide synthase as compared to WT. Mechanistically, gene expression and ultrastructural analysis of microglia suggested a defect in myelin degradation and phagosome processing during CPZ intoxication in TREM2(-/-) microglia. These findings place TREM2 as a key regulator of microglia activation in vivo in response to tissue damage. Two STAGE (6weeks 12 weeks),
2015-07-06 | E-GEOD-70475 | biostudies-arrayexpress
Project description:While macrophage heterogeneity during Metabolic dysfunction-associated steatohepatitis (MASH) has been described, the fate of these macrophages during MASH regression is poorly understood. Comparing macrophage heterogeneity during MASH progression vs regression, we identified specific macrophage sub- populations that are critical for MASH/fibrosis resolution. We elucidated the restorative pathways and gene signatures that define regression associated macrophages (RAM) and establish the importance of TREM2+ macrophages during MASH regression. Liver resident Kupffer cells are lost during MASH and are replaced by four distinct monocyte derived macrophage sub-populations. Trem2 is expressed in two macrophage sub- populations: (i) monocyte-derived macrophages occupying the Kupffer cell niche (MoKC) and (ii) lipid-associated macrophages (LAM). In regression livers, no new transcriptionally distinct MF sub-population emerged. However, the relative macrophage composition changed during regression compared to MASH. While MoKC was the major macrophage sub-population during MASH, they decreased during regression. LAM was the dominant macrophage sub-type during MASH regression and maintained Trem2 expression. Both MoKC and LAM were enriched in disease resolving pathways. Absence of TREM2 restricted the emergence of LAMs and formation of hepatic crown like structures (hCLS). TREM2+ macrophages are functionally important not only for restricting MASH-fibrosis progression, but also for effective regression of inflammation and fibrosis. TREM2+ MF are superior collagen degraders. Lack of TREM2+ macrophages also prevented elimination of hepatic steatosis and inactivation of HSC during regression, indicating their significance in metabolic co-ordination with other cell- types in the liver. TREM2 imparts this protective effect through multifactorial mechanisms, including improved phagocytosis, lipid-handling and collagen degradation.
2024-08-05 | GSE261829 | GEO